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Old 28th May 2013, 01:04 AM   #1
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Default UcD Philips UM10155 LTspice simulation

Hello, I had great fun simulating the UcD module Philips UM10155. Can somebody check the waveforms ?
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File Type: gif UcD simplified (schema).GIF (19.1 KB, 310 views)
File Type: jpg UcD simplified (simulation result).JPG (248.3 KB, 306 views)
File Type: jpg UcD simplified (drain currents).JPG (242.3 KB, 300 views)
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Old 28th May 2013, 12:20 PM   #2
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In the philips circuit, R9 330ohm controls deadtime. As default the philips eval module comes set to high efficiency mode (long deadtime).

Play around with the value of this resistor and see what changes that brings in simulation THD.

Also play around a bit with the resistor in the phase lead network and see what changes a increase or decrease in switching frequency gives in simulation THD.
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Old 28th May 2013, 03:56 PM   #3
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Quote:
Originally Posted by Tekko View Post
In the philips circuit, R9 330ohm controls deadtime. As default the philips eval module comes set to high efficiency mode (long deadtime). Play around with the value of this resistor and see what changes that brings in simulation THD.
Thank you, indeed R9 value is critical. A low value induces cross conduction spikes. A high value adds deadtime, preventing cross conduction spikes. Past the optimal value where the cross conduction spikes get eradicated, the distortion increase. Actually the lowest distortion occurs when there remain visible crossover spikes, same spike magnitude as the coil ripple current at idle. EMI will be badly impacted. This is of course on simulation. Don't know if the real world behaves this way.
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Old 30th May 2013, 10:14 AM   #4
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I'm planning to prototype this discrete comparator and see how it compares to the ic based on im currently using.

A template has been made to aid putting it together:
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Old 30th May 2013, 02:21 PM   #5
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I think that you better can judge performance, by designing a single PCB containing everything, including the comparator/modulator, power MOSFETs, local power supplies, filtering capacitors and filtering coil. Will you try this? Please specify Philips and NXP components all-round. I'm willing to order PCBs for building such amp. Supply rails say +42V and -42V, no more.
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Old 30th May 2013, 03:08 PM   #6
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I have a test power module that takes the differential signals in from the PUT (Prototype Under Test) IE i dont design a full amp board until i i have prototyped the modulator section and tested it.
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Old 30th May 2013, 03:40 PM   #7
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Quote:
Originally Posted by Tekko View Post
I have a test power module that takes the differential signals in from the PUT (Prototype Under Test) IE i dont design a full amp board until i i have prototyped the modulator section and tested it.
Have you considered an epoxy prototyping board for the comparator/modulator?
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Old 30th May 2013, 03:51 PM   #8
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That is what i was gonna solder it together on. That cadded template was so i know beforehand how to place the transistors and wires.


Either way heres the layout for the ic based UcD, which was ordered today from seedstudio, am currently listening to music on the prototype.

Last edited by Tekko; 30th May 2013 at 03:54 PM.
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Old 30th May 2013, 11:24 PM   #9
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Please consider adding a cascode. See schema.
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Old 31st May 2013, 02:48 PM   #10
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Noise floor of discrete UcD with cascode, using only 2N5401/2N5551. This comparator is basically what you find in the NCORE circuit.
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